Process for the manufacture of concrete having a high electric insulation resistance



Patented Apr. 21, 1936 UNITED STATES PROCESS FOR THE MANUFACTURE OFCONCRETE HAVING A HIGHELECTRIC INSULATION RESISTANCE Emile PierreClaudius Lambert, Paris, France No Drawing. Application January 25,1932, Serial No. 588,840. In France January 29, 1931 4 Claims.

This invention has for object a process for the manufacture of concretehaving a high electric insulation resistance. It consists in mixingcement, impalpable silica, silicious gravel or broken silicious stone,extra-silicious sand, and diluting these materials with water, whichcontains bituminous materials or flower of sulphur. After completesetting of the concrete obtained the same is heat treated and coveredwith one or more layers of products of the above named category, or ofproducts such as resinate of soda, bakelite and other insulatingmaterials.

It is obvious that certain materials above indicated might be replacedby materials capable of fulfilling the same function.

The concrete manufactured according to the process forming thesubject-matter of the present invention, has remarkable dielectricproperties and constitutes a high grade waterproof insulating material.It has moreover the advantage of being of a cost price much lower thanthat of the insulating materials hitherto employed.

It is particularly suitable for the manufacture of insulators, fortelegraphic and telephonic lines and for electric power supply lines, aswell as for the manufacture of insulating members supporting the railsor current supply wires of electrified railroad plants.

The invention also relates to the articles such as posts, for supportingarms, insulators, railway sleepers, partitions, switchboards in electricpower generating or receiving stations, insulating vats and the like,made of the special concrete above indicated, with or withoutincorporation of bituminous or like materials. This concrete, withoutbeing subjected to a treatment by heat, is rendered dielectric byapplication of one or more layers of products of the same category asthose used for the manufacture of the concrete itself, or of productsthe main ingredient of which is resinate of soda, bakelite or otherinsulating substances.

The parts or members made of the said special concrete can be obtainedby the ordinary methods or'also by trepidation, vibration or compressionin suitable moulds or casings.

The following proportions, given by way of example only, can be employedfor the manufacture of a concrete of the present invention having a highelectric insulation resistance:

Cement 300 to 400 kgs.

Water (in variable quantity according to the season) The bituminousmaterials, about 250 kgs. for one cubic meter of finished product, whichcan be added when diluting are the following: tar or pitch obtained fromstearine, asphalt, petroleum oil, etc. in the form of an emulsion.

The treatment by heat is efiected in a furnace or in a digester at atemperature of about 140 to 150 C. When use is made of a digester, thelayers of the superficial coating can be replaced by an impregnationunder pressure.

The applicant has found that the cements which give the best results arealuminous cements, so-called melted-cements and more particularly thosemanufactured by the Socit des Ciments de Lafarge et du Teil, at theVitry-le- Francois and du Teil Works, so-called Waterjacket manufacture.

It is obvious that the process above set forth can give rise to numerousmodifications which obviously are all included in the scope of thepresent invention.

What I claim as my invention and desire to secure by Letters Patent is:

1. Process for the manufacture of products made of materials having ahigh mechanical resistance and high electric insulating qualities, whichconsists in first mixing, in the cold state, fused aluminous cement,silicious gravel, supersilicious sand, impalpable silica, water insufiicient quantity for the setting of the cement, and bituminousmaterials in a finely divided condition, then shaping the product incold state, and final-- 1y subjecting the product to a heat treatment atabout 140 C. after setting of the cement.

2. Process for the manufacture of products made of materials having ahigh mechanical resistance and high electric insulating qualities, whichconsists in first mixing, in the cold state, fused aluminous cement,silicious gravel, supersilicious sand, impalpable silica, water insufilcient quantity for the setting of the cement, and flowers ofsulphur in a finely divided condition, then shaping the product in coldstate and finally subjecting the product to a heat treatment at about140 C. after setting of the cement.

3. Process for the manufacture of products made of materials having ahigh mechanical resistance and high electric insulating qualities, whichconsists in first mixing, in the cold state, fused aluminous cement,silicious gravel, supersilicious sand, impalpable silica, water insufiicient quantity for the setting of the cement, and bituminousmaterials in a finely divided condition, then shaping the product incold state, subjecting the product to a heat treatment at about 140 C.after setting of the cement, and finally coating in cold state theproduct after its heat treatment, with a bituminous material similar tothat incorporated in the mass.

4. Process for the manufacture of products made of materials having ahigh mechanical resistance and high electric insulating qualities, whichconsists in first mixing in cold state, fused aluminous cement,silicious gravel, super-silicious sand, impalpable silica, water insufficient quantity for the setting of the cement, and bituminousmaterials in a finely divided condition, then shaping the product incold state and subjecting the product to a heat treatment at about 140C. after setting of the cement, and finally coating, in cold state, theproduct after its heat treatment, with resinate of soda.

EMILE PIERRE CLAUDIUS LAMBERT.

